International Telecommunication Union (ITU) has high requirements for performances of the next generation communication system (IMT-Advanced). For example, it is required that the maximum system transmission bandwidth should reach 100 MHz, the peak data rate of uplink and downlink data transmission should reach 1 Gbps and 500 Mbps respectively. There are also very high requirements for average spectrum efficiency of the system, especially for cell edge spectrum efficiency. In order to meet the requirements for the IMT-Advanced system, 3GPP proposed to apply coordinated multi-point (CoMP) transmission technique to 3GPP's next generation cellular mobile communication system, i.e. e., the Long Term Evolution (LTE)-Advanced system, to improve system performance. To facilitate description, a user device participating in CoMP transmission is referred to as a CoMP UE, a user device not participating in the CoMP transmission is referred to as a non-CoMP UE. Correspondingly, a cell adopting CoMP transmission is referred to as a CoMP cell, or coordinated cell for short. Different CoMP UEs may be served by different CoMP cells or the same CoMP cells.
Each UE, either a CoMP UE or a non-CoMP UE, has an anchor cell. The anchor cell of a non-CoMP UE may be the serving cell of the UE. A non-CoMP UE receives control information and data from its anchor cell. A CoMP UE receives control information from its anchor cell, and receives data from its anchor cell and/or a CoMP cell.
CoMP transmission technique is a mobile transmission technique which transmits and receives data or signaling through cooperation of multiple transmitting points distributed at different geographical locations. The multiple transmitting points may be base stations (eNodeB) of different cells. CoMP transmission includes downlink coordinated transmission and uplink joint reception. Downlink CoMP transmission has two types of schemes: joint scheduling and coordinated transmission. Joint scheduling refers to allocating orthogonal or quasi-orthogonal resources to different UEs through coordination of cells in time resources, frequency resources and spatial resources to avoid interference. Coordinated transmission refers to simultaneous data transmission to the same UE by base stations of multiple cells.
Therefore, embodiments provide a method and an apparatus for configuring SRS for CoMP transmission, to reduce interference between SRS in CoMP cells.